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Pervasiveness of Alzheimer's disease (AD) across the globe is on rise, devitalizing the essential brain functions of the afflicted individual. Multiple neurological pathways viz., cholinergic, amyloidogenic and tau protein pathways underlying the disease and interdependence make it more complex to develop effective treatment strategies. Existing drug treatments for Alzheimer's disease majorly belong to the class of cholinergic inhibitors which improve the behavioral symptoms. But there are no drugs that could arrest the disease progression. Inhibition of beta secretase enzyme could prevent the deposition of amyloid plaques in the neurons, thereby arresting the disease progression. Search for novel drugs to treat the underlying pathogenesis of the disease is pivotal in this day and age. The source of most active lead molecules discovered recently is from the nature. Marine ecosystem provides a plethora of pharmacologically lead molecules from various living organisms inhabiting the sea. Among all, marine microbes are the most under-explored and indispensable source of many bioactive metabolites. Studies have been reported on potent metabolites from marine microbes which could inhibit the key enzymes involved in the AD pathogenesis. The advancement in microbial bioprospecting and molecular biology techniques have eased the process of cultivation and identification of microbes, isolation of novel bioactive metabolites of clinical use. Exploring such marine natural resources for pharmacological lead molecules could give a breakthrough in the drug discovery domain for treating AD such debilitating diseases. In this review, a comprehensive account of bioprospecting methods and reports of marine microbial isolates are discussed., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Introduction: RNA interference has become a tool of choice in the development of drugs in various therapeutic areas of Post Transcriptional Gene Silencing (PTGS). The critical element in developing successful RNAi therapeutics lies in designing small interfering RNA (siRNA) using an efficient algorithm satisfying the designing criteria. Further, translation of siRNA from bench-side to bedside needs an efficient delivery system and/or chemical modification. Areas covered: This review emphasizes the importance of dicer, the criteria for efficient siRNA design, the currently available algorithms and strategies to overcome off-target effects, immune stimulatory effects and endosomal trap. Expert opinion: Specificity and stability are the primary concerns for siRNA therapeutics. The design criteria and algorithms should be chosen rationally to have a siRNA sequence that binds to the corresponding mRNA as it happens in the Watson and Crick base pairing. However, it must evade a few more hurdles (Endocytosis, Serum stability etc.) to be functional in the cytosol.

Bcl-2, an antiapoptotic protein, is considered as a potential target in cancer treatment since its oncogenic potential has been proven and is well documented. Antisense technology and RNA interference (RNAi) have been used to reduce the expression of the Bcl-2 gene in many types of cancer cells and are effective as adjuvant therapy along with the chemotherapeutic agents. The lack of appropriate delivery systems is considered to be the main hurdle associated with the RNAi. In this review, we discuss the antiapoptotic Bcl-2 protein, its oncogenic potential, and various approaches utilized to target Bcl-2 including suitable delivery systems employed for successful delivery of siRNA.

Even after 20 years of granting orphan status for chondroitinase by US FDA, there is no visible outcome in terms of clinical use. The reasons are many. One of them could be lack of awareness regarding the biological application of the enzyme. The biological activity of chondroitinase is due to its ability to act on chondroitin sulfate proteoglycans (CSPGs). CSPGs are needed for normal functioning of the body. An increase or decrease in the level of CSPGs results in various pathological conditions. Chondroitinase is useful in conditions where there is an increase in the level of CSPGs, namely spinal cord injury, vitreous attachment and cancer. Over the last decade, various animal studies showed that chondroitinase could be a good drug candidate. Research focusing on developing a suitable carrier system for delivering chondroitinase needs to be carried out so that pharmacological activity observed in vitro and preclinical studies could be translated to clinical use. Further studies on distribution of chondroitinase as well need to be focused so that chondroitinase with desired attributes could be discovered. The present review article discusses about various biological applications of chondroitinase, drug delivery systems to deliver the enzyme and distribution of chondroitinase among microbes.

Hyaluronidase is an enzyme that catalyzes breakdown of hyaluronic acid. This property is utilized for hypodermoclysis and for treating extravasation injury. Hyaluronidase is further studied for possible application as an adjuvant for increasing the efficacy of other drugs. Development of suitable carrier system for hyaluronidase would help in coadministration of other drugs. In the present study, the hyaluronidase was encapsulated in liposomes. The effect of variables, namely, phosphatidylcholine (PC), cholesterol, temperature during film formation (T 1), and speed of rotation of the flask during film formation (SPR) on percentage of protein encapsulation, was first analyzed using factorial design. The study showed that level of phosphatidylcholine had the maximum effect on the outcome. The effect of interaction of PC and SPR required for preparation of nanoliposomes was identified by central composite design (CCD). The dependent variables were percentage protein encapsulation, particle size, and zeta potential. The study showed that ideal conditions for production of hyaluronidase loaded nanoliposomes are PC-140 mg and cholesterol 1/5th of PC when the SPR is 150 rpm and T 1 is 50°C.

Context: Poly(beta-amino ester) (PBAE) with its pH sensitiveness and Poly(lactic-co-glycolic acid) (PLGA) with huge DNA cargo capacity in combination prove to be highly efficient as DNA delivery system., Objective: To study the effectiveness of novel synthesized PBAE polymer with PLGA blend at different ratios in DNA vaccine delivery., Methods: In the present study, multifunctional polymer blend microparticles using a combination of PLGA and novel PBAE polymers A1 (bis(3-(propionyloxy)propyl)3,3'-(propane-1,3-diyl-bis(methylazanediyl))dipropanoate) and A2 (bis(4-(propionyloxy)butyl)3,3'-(ethane-1,2-diyl-bis(isopropylazanediyl))dipropanoate) at different ratios (85:15, 75:25, and 50:50) were prepared by double emulsion solvent removal method. The microparticles were characterized for cytotoxicity, transfection efficiency, and DNA encapsulation efficiency., Result: It was evident from results that among the microparticles prepared with PLGA/PBAE blend the PLGA:PBAE at 85:15 ratio was found to be more effective combination than the microparticles prepared with PLGA alone in terms of transfection efficiency and better DNA integrity. Microparticles made of PLGA and PBAE A1 at 85:15 ratio, respectively, were found to be less toxic when compared with microparticles prepared with A2 polymer., Conclusion: The results encourage the use of the synthesized PBAE polymer in combination with PLGA as an effective gene delivery system.

Catechin is a known hepatoprotective and anticancer agent but has limited bioavailability. Its apoptotic signaling pathway in human hepatocellular carcinoma is vaguely explored. Thus, this study was designed to explore cytotoxicity by MTT assay, induction of apoptosis via DNA fragmentation, nuclear staining, bivariate flow cytometric analysis using annexin V- FITC and propidium iodide, cell cycle analysis and apoptotic markers by RT-PCR and western blotting in HepG2 cells. To increase the bioavailability and selectivity to cancer cells, various liposomes of catechin viz., conventional, charged and PEGylated forms were prepared by film hydration method and evaluated for cytotoxicity in vitro in HepG2 cells and in in vivo in EAC-induced liquid tumor model. Catechin and catechin liposomes inhibited the growth of HepG2 cell lines at concentrations 100-200 μg mL(-1) depending on the length of exposure. It induced apoptosis and inhibited G₂/M phase in cell cycle analysis. Catechin downregulated Bcl-2, initiated the release of cytochrome c into the cytosol and upregulated Bax, caspase-3,-9 and p53 in the HepG2 cells. Catechin and its liposomal formulation, at a dose of 200mg/kg body weight was found to be significantly (p<0.05) effective in inhibiting percentage increase in body weight and enhancing the mean survival time. Deviated hematological parameters, antioxidant parameters (superoxide dismutase, catalase and lipid peroxidation) and LFT in tumor bearing mice were found to be significantly (p<0.05) restored towards normal after treatment with catechin and its liposomes., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Potential use of siRNA as therapeutic agent has elicited a great deal of interest. However, insufficient cellular uptake and poor stability limited its application in therapeutics. In our earlier study, we prepared PLGA nanoparticles for effective delivery of siRNA targeting Bcl-2 gene to block its expression. Purpose of the present study was to improve effectiveness of PLGA nanoformulation of siRNA targeting anti-apoptotic Bcl-2 gene through chitosan coating. We prepared chitosan coated PLGA nanoparticles by using the double emulsion solvent diffusion (DESE) method. Characterization of prepared chitosan coated nanoformulation was done followed by cytotoxicity studies, expression studies and in vivo studies. Particle size of chitosan coated nanoparticles was found to be increased compared to PLGA nanoparticles from 244 to 319 nm. Surface charge of chitosan coated nanoparticles was found to be positive facilitating transfection of nanoformulation into cells. In vitro studies indicated increased transfection of nanoparticles resulting in effective silencing of Bcl-2. Marked apoptotic lesions were observed in nuclear staining studies. On comparison of the results from the present study with those of previous study, it was found that the extent of silencing of Bcl-2 gene by PLGA nanoformulation has improved significantly through chitosan coating. In vivo studies showed significant tumor regression in animals treated with chitosan coated PLGA nanoformulation of siRNA., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The purpose of this research work was to prepare poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles for delivery of siRNA (small interfering RNA) for silencing anti-apoptotic Bcl-2 gene in cancerous cells by using the double emulsion solvent diffusion (DESE) method. Overexpression of Bcl-2 is often seen in a wide variety of human cancers. This prevents the induction of programmed cell death (i.e., apoptosis) in cancerous cells. It is also reported that over-expression of Bcl-2 contributes to resistance in chemotherapy and inhibits the apoptosis induced by chemotherapeutic agents. Agents antagonizing the anti-apoptotic Bcl-2 protein have been shown to restore normal apoptotic processes in cancer cells. RNA interference (RNAi) has emerged as an efficient and selective technique for gene silencing, siRNA mediated gene silencing has been used in a wide variety of disease condition. PLGA nanoparticles were able to completely bind siRNA and to provide protection for siRNA against nuclease degradation. In vitro cell culture studies subsequently revealed that PLGA nanoparticles with adsorbed siRNA could efficiently silence the targeted anti-apoptotic Bcl-2 gene in mammalian cells. In vivo studies results showed that siRNA was effectively delivered through nanoparticles and there was significant decrease in the tumor volume.